The series "Blue Exorcist" had its beginnings in manga form. In it, humans and demons reside in different realms -- Assiah and Gehenna, respectively -- that usually don't intersect. But now, demons are starting to enter the tangible world of the human race and must be culled. Thankfully, there are people who can exorcise them. Rin Okumura, a young man of strange origins and exceptional power, sets out to rid the world of the evil spirits in an effort to be the ultimate exorcist and hero. Accomplishing that would mean defeating his own father, Satan.